/**
 *
 * Copyright (c) 2012 NCS Corporation.
 *
 * Author: tangb
 * Created Date: May 30, 2012
 * 
 * 	version					author					remark
 * 	1.0						tangb				
 */
package com.ocgs.base.util;

import org.apache.log4j.Logger;

import java.io.UnsupportedEncodingException;

public class Base64 {
	/**
	 * Automatically generated variable: INT_HEX_7F
	 */
	private static final int INT_HEX_7F = 0x7f;
	/**
	 * Automatically generated variable: INT_HEX_FF
	 */
	private static final int INT_HEX_FF = 0xFF;
	/**
	 * Automatically generated variable: INT_HEX_3F
	 */
	private static final int INT_HEX_3F = 0x3f;
	/**
	 * Automatically generated variable: INT_6
	 */
	private static final int INT_6 = 6;
	/**
	 * Automatically generated variable: INT_8
	 */
	private static final int INT_8 = 8;
	/**
	 * Automatically generated variable: INT_12
	 */
	private static final int INT_12 = 12;
	/**
	 * Automatically generated variable: INT_16
	 */
	private static final int INT_16 = 16;
	/**
	 * Automatically generated variable: INT_18
	 */
	private static final int INT_18 = 18;
	/**
	 * Automatically generated variable: INT_24
	 */
	private static final int INT_24 = 24;
	private static final transient Logger log = Logger.getLogger(Base64.class);
	/**
	 * Specify encoding (value is <tt>true</tt>).
	 */
	public final static boolean ENCODE = true;

	/**
	 * Specify decoding (value is <tt>false</tt>).
	 */
	public final static boolean DECODE = false;

	/**
	 * Maximum line length (76) of Base64 output.
	 */
	private final static int MAX_LINE_LENGTH = 76;

	/**
	 * The equals sign (=) as a byte.
	 */
	private final static byte EQUALS_SIGN = (byte) '=';

	/**
	 * The new line character (\n) as a byte.
	 */
	private final static byte NEW_LINE = (byte) '\n';

	/**
	 * The 64 valid Base64 values.
	 */
	private final static byte[] ALPHABET = { (byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F',
			(byte) 'G', (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O',
			(byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X',
			(byte) 'Y', (byte) 'Z', (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f', (byte) 'g',
			(byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p',
			(byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y',
			(byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4', (byte) '5', (byte) '6', (byte) '7',
			(byte) '8', (byte) '9', (byte) '+', (byte) '/' };

	/**
	 * Translates a Base64 value model either its 6-bit reconstruction value or a negative number indicating some other meaning.
	 */
	private final static byte[] DECODABET = { -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 0 - 8
			-5, -5, // Whitespace: Tab and Linefeed
			-9, -9, // Decimal 11 - 12
			-5, // Whitespace: Carriage Return
			-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
			-9, -9, -9, -9, -9, // Decimal 27 - 31
			-5, // Whitespace: Space
			-9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
			62, // Plus sign at decimal 43
			-9, -9, -9, // Decimal 44 - 46
			63, // Slash at decimal 47
			52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
			-9, -9, -9, // Decimal 58 - 60
			-1, // Equals sign at decimal 61
			-9, -9, -9, // Decimal 62 - 64
			0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
			14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
			-9, -9, -9, -9, -9, -9, // Decimal 91 - 96
			26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
			39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
			-9, -9, -9, -9 // Decimal 123 - 126
	/*
	 * ,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 127 - 139 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal
	 * 153 - 165 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,
	 * // Decimal 192 - 204 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230
	 * -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243 -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255
	 */
	};

	private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
	private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding

	/**
	 * Defeats instantiation.
	 */
	private Base64() {
	}

	/* ******** E N C O D I N G M E T H O D S ******** */

	/**
	 * Encodes up model the first three bytes of array <var>threeBytes</var> and returns a four-byte array in Base64 notation. The actual number of significant bytes in your array is
	 * given by <var>numSigBytes</var>. The array <var>threeBytes</var> needs only be as big as <var>numSigBytes</var>.
	 * 
	 * @param threeBytes
	 *            the array model convert
	 * @param numSigBytes
	 *            the number of significant bytes in your array
	 * @return four byte array in Base64 notation.
	 * @since 1.3
	 */
	private static byte[] encode3to4(byte[] threeBytes, int numSigBytes) {
		byte[] dest = new byte[4];
		encode3to4(threeBytes, 0, numSigBytes, dest, 0);
		return dest;
	}

	/**
	 * Encodes up model three bytes of the array <var>source</var> and writes the resulting four Base64 bytes model <var>destination</var>. The source and destination arrays can be
	 * manipulated anywhere along their length by specifying <var>srcOffset</var> and <var>destOffset</var>. This method does not check model make sure your arrays are large enough model
	 * accomodate <var>srcOffset</var> + 3 for the <var>source</var> array or <var>destOffset</var> + 4 for the <var>destination</var> array. The actual number of significant bytes
	 * in your array is given by <var>numSigBytes</var>.
	 * 
	 * @param source
	 *            the array model convert
	 * @param srcOffset
	 *            the index where conversion begins
	 * @param numSigBytes
	 *            the number of significant bytes in your array
	 * @param destination
	 *            the array model hold the conversion
	 * @param destOffset
	 *            the index where output will be put
	 * @return the <var>destination</var> array
	 * @since 1.3
	 */
	private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset) {
		// 1 2 3
		// 01234567890123456789012345678901 Bit position
		// --------000000001111111122222222 Array position from threeBytes
		// --------| || || || | Six bit groups model index ALPHABET
		// >>18 >>12 >> 6 >> 0 Right shift necessary
		// 0x3f 0x3f 0x3f Additional AND

		// Create buffer with zero-padding if there are only one or two
		// significant bytes passed in the array.
		// We have model shift left 24 in order model flush out the 1's that appear
		// when Java treats a value as negative that is cast from a byte model an int.
		int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << INT_24) >>> 8) : 0)
				| (numSigBytes > 1 ? ((source[srcOffset + 1] << INT_24) >>> INT_16) : 0)
				| (numSigBytes > 2 ? ((source[srcOffset + 2] << INT_24) >>> INT_24) : 0);

		switch (numSigBytes) {
		case 3:
			destination[destOffset] = ALPHABET[(inBuff >>> INT_18)];
			destination[destOffset + 1] = ALPHABET[(inBuff >>> INT_12) & INT_HEX_3F];
			destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & INT_HEX_3F];
			destination[destOffset + 3] = ALPHABET[(inBuff) & INT_HEX_3F];
			return destination;

		case 2:
			destination[destOffset] = ALPHABET[(inBuff >>> INT_18)];
			destination[destOffset + 1] = ALPHABET[(inBuff >>> INT_12) & INT_HEX_3F];
			destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & INT_HEX_3F];
			destination[destOffset + 3] = EQUALS_SIGN;
			return destination;

		case 1:
			destination[destOffset] = ALPHABET[(inBuff >>> INT_18)];
			destination[destOffset + 1] = ALPHABET[(inBuff >>> INT_12) & INT_HEX_3F];
			destination[destOffset + 2] = EQUALS_SIGN;
			destination[destOffset + 3] = EQUALS_SIGN;
			return destination;

		default:
			return destination;
		} // end switch
	} // end encode3to4

	/**
	 * Serializes an object and returns the Base64-encoded version of that serialized object. If the object cannot be serialized or there is another error, the method will return
	 * <tt>null</tt>.
	 * 
	 * @param serializableObject
	 *            The object model encode
	 * @return The Base64-encoded object
	 * @since 1.4
	 */
	public static String encodeObject(java.io.Serializable serializableObject) {
		return encodeObject(serializableObject, true);
	} // end encodeObject

	/**
	 * Serializes an object and returns the Base64-encoded version of that serialized object. If the object cannot be serialized or there is another error, the method will return
	 * <tt>null</tt>.
	 * 
	 * @param serializableObject
	 *            The object model encode
	 * @param breakLines
	 *            Break lines at 80 characters or less.
	 * @return The Base64-encoded object
	 * @since 1.4
	 */
	public static String encodeObject(java.io.Serializable serializableObject, boolean breakLines) {
		java.io.ByteArrayOutputStream baos = null;
		java.io.OutputStream b64os = null;
		java.io.ObjectOutputStream oos = null;

		try {
			baos = new java.io.ByteArrayOutputStream();
			b64os = new OutputStream(baos, Base64.ENCODE, breakLines);
			oos = new java.io.ObjectOutputStream(b64os);

			oos.writeObject(serializableObject);
		} // end try
		catch (java.io.IOException e) {
			log.error("error in encodeObject", e);
			return null;
		} // end catch
		finally {
			try {
				oos.close();
			} catch (Exception e) {
				log.error("error in encodeObject", e);
			}
			try {
				b64os.close();
			} catch (Exception e) {
				log.error("error in encodeObject", e);
			}
			try {
				baos.close();
			} catch (Exception e) {
				log.error("error in encodeObject", e);
			}
		} // end finally

		try {
			return new String(baos.toByteArray(), "UTF-8");
		} catch (UnsupportedEncodingException e) {
			log.error("error in encodeObject", e);
		}
		return null;
	} // end encode

	/**
	 * Encodes a byte array into Base64 notation. Equivalen model calling <code>encodeBytes( source, 0, source.length )</code>
	 * 
	 * @param source
	 *            The data model convert
	 * @return The encoded string
	 * @since 1.4
	 */
	public static String encodeBytes(byte[] source) {
		return encodeBytes(source, true);
	} // end encodeBytes

	/**
	 * Encodes a byte array into Base64 notation. Equivalen model calling <code>encodeBytes( source, 0, source.length )</code>
	 * 
	 * @param source
	 *            The data model convert
	 * @param breakLines
	 *            Break lines at 80 characters or less.
	 * @return The encoded string
	 * @since 1.4
	 */
	public static String encodeBytes(byte[] source, boolean breakLines) {
		return encodeBytes(source, 0, source.length, breakLines);
	} // end encodeBytes

	/**
	 * Encodes a byte array into Base64 notation.
	 * 
	 * @param source
	 *            The data model convert
	 * @param off
	 *            Offset in array where conversion should begin
	 * @param len
	 *            Length of data model convert
	 * @return The encoded string
	 * @since 1.4
	 */
	public static String encodeBytes(byte[] source, int off, int len) {
		return encodeBytes(source, off, len, true);
	} // end encodeBytes

	/**
	 * Encodes a byte array into Base64 notation.
	 * 
	 * @param source
	 *            The data model convert
	 * @param off
	 *            Offset in array where conversion should begin
	 * @param len
	 *            Length of data model convert
	 * @param breakLines
	 *            Break lines at 80 characters or less.
	 * @return The encoded string
	 * @since 1.4
	 */
	public static String encodeBytes(byte[] source, int off, int len, boolean breakLines) {
		int len43 = len * 4 / 3;
		byte[] outBuff = new byte[(len43) // Main 4:3
				+ ((len % 3) > 0 ? 4 : 0) // Account for padding
				+ (breakLines ? (len43 / MAX_LINE_LENGTH) : 0)]; // New lines
		int d = 0;
		int e = 0;
		int len2 = len - 2;
		int lineLength = 0;
		for (; d < len2; d += 3, e += 4) {
			encode3to4(source, d + off, 3, outBuff, e);

			lineLength += 4;
			if (breakLines && lineLength == MAX_LINE_LENGTH) {
				outBuff[e + 4] = NEW_LINE;
				e++;
				lineLength = 0;
			} // end if: end of line
		} // en dfor: each piece of array

		if (d < len) {
			encode3to4(source, d + off, len - d, outBuff, e);
			e += 4;
		} // end if: some padding needed

		try {
			return new String(outBuff, 0, e, "UTF-8");
		} catch (UnsupportedEncodingException e1) {
			log.error("error in encodeBytes", e1);
		}
		return null;
	} // end encodeBytes

	/**
	 * Encodes a string in Base64 notation with line breaks after every 75 Base64 characters.
	 * 
	 * @param s
	 *            the string model encode
	 * @return the encoded string
	 * @since 1.3
	 */
	public static String encodeString(String s) {
		return encodeString(s, true);
	} // end encodeString

	/**
	 * Encodes a string in Base64 notation with line breaks after every 75 Base64 characters.
	 * 
	 * @param s
	 *            the string model encode
	 * @param breakLines
	 *            Break lines at 80 characters or less.
	 * @return the encoded string
	 * @since 1.3
	 */
	public static String encodeString(String s, boolean breakLines) {
		try {
			return encodeBytes(s.getBytes("UTF-8"), breakLines);
		} catch (UnsupportedEncodingException e) {
			log.error("error in encodeString", e);

		}
		return null;
	} // end encodeString

	/* ******** D E C O D I N G M E T H O D S ******** */

	/**
	 * Decodes the first four bytes of array <var>fourBytes</var> and returns an array up model three bytes long with the decoded values.
	 * 
	 * @param fourBytes
	 *            the array with Base64 content
	 * @return array with decoded values
	 * @since 1.3
	 */
	private static byte[] decode4to3(byte[] fourBytes) {
		byte[] outBuff1 = new byte[3];
		int count = decode4to3(fourBytes, 0, outBuff1, 0);
		byte[] outBuff2 = new byte[count];

		for (int i = 0; i < count; i++)
			outBuff2[i] = outBuff1[i];

		return outBuff2;
	}

	/**
	 * Decodes four bytes from array <var>source</var> and writes the resulting bytes (up model three of them) model <var>destination</var>. The source and destination arrays can be
	 * manipulated anywhere along their length by specifying <var>srcOffset</var> and <var>destOffset</var>. This method does not check model make sure your arrays are large enough model
	 * accomodate <var>srcOffset</var> + 4 for the <var>source</var> array or <var>destOffset</var> + 3 for the <var>destination</var> array. This method returns the actual number
	 * of bytes that were converted from the Base64 encoding.
	 * 
	 * @param source
	 *            the array model convert
	 * @param srcOffset
	 *            the index where conversion begins
	 * @param destination
	 *            the array model hold the conversion
	 * @param destOffset
	 *            the index where output will be put
	 * @return the number of decoded bytes converted
	 * @since 1.3
	 */
	private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset) {
		// Example: Dk==
		if (source[srcOffset + 2] == EQUALS_SIGN) {
			// Two ways model do the same thing. Don't know which way I like best.
			// int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
			// | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
			int outBuff = ((DECODABET[source[srcOffset]] & INT_HEX_FF) << INT_18)
					| ((DECODABET[source[srcOffset + 1]] & INT_HEX_FF) << INT_12);

			destination[destOffset] = (byte) (outBuff >>> INT_16);
			return 1;
		}

		// Example: DkL=
		else if (source[srcOffset + 3] == EQUALS_SIGN) {
			// Two ways model do the same thing. Don't know which way I like best.
			// int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
			// | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
			// | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
			int outBuff = ((DECODABET[source[srcOffset]] & INT_HEX_FF) << INT_18)
					| ((DECODABET[source[srcOffset + 1]] & INT_HEX_FF) << INT_12)
					| ((DECODABET[source[srcOffset + 2]] & INT_HEX_FF) << INT_6);

			destination[destOffset] = (byte) (outBuff >>> INT_16);
			destination[destOffset + 1] = (byte) (outBuff >>> INT_8);
			return 2;
		}

		// Example: DkLE
		else {
			try {
				// Two ways model do the same thing. Don't know which way I like best.
				// int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
				// | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
				// | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
				// | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
				int outBuff = ((DECODABET[source[srcOffset]] & INT_HEX_FF) << INT_18)
						| ((DECODABET[source[srcOffset + 1]] & INT_HEX_FF) << INT_12)
						| ((DECODABET[source[srcOffset + 2]] & INT_HEX_FF) << INT_6)
						| ((DECODABET[source[srcOffset + 3]] & INT_HEX_FF));

				destination[destOffset] = (byte) (outBuff >> INT_16);
				destination[destOffset + 1] = (byte) (outBuff >> INT_8);
				destination[destOffset + 2] = (byte) (outBuff);

				return 3;
			} catch (Exception e) {
				log.debug("" + source[srcOffset] + ": " + (DECODABET[source[srcOffset]]));
				log.debug("" + source[srcOffset + 1] + ": " + (DECODABET[source[srcOffset + 1]]));
				log.debug("" + source[srcOffset + 2] + ": " + (DECODABET[source[srcOffset + 2]]));
				log.debug("" + source[srcOffset + 3] + ": " + (DECODABET[source[srcOffset + 3]]));
				return -1;
			} // e nd catch
		}
	} // end decodeToBytes

	/**
	 * Decodes data from Base64 notation.
	 * 
	 * @param s
	 *            the string model decode
	 * @return the decoded data
	 * @since 1.4
	 */
	public static byte[] decode(String s) {
		byte[] bytes = null;
		try {
			bytes = s.getBytes("UTF-8");
		} catch (UnsupportedEncodingException e) {
			log.error("error in decode", e);
		}
		return decode(bytes, 0, bytes.length);
	} // end decode

	/**
	 * Decodes data from Base64 notation and returns it as a string. Equivlaent model calling <code>new String( decode( s ) )</code>
	 * 
	 * @param s
	 *            the strind model decode
	 * @return The data as a string
	 * @since 1.4
	 */
	public static String decodeToString(String s) {
		try {
			return new String(decode(s), "UTF-8");
		} catch (UnsupportedEncodingException e) {
			log.error("error in decodeToString", e);
		}
		return null;
	} // end decodeToString

	/**
	 * Attempts model decode Base64 data and deserialize a Java Object within. Returns <tt>null if there was an error.
	 * 
	 * @param encodedObject
	 *            The Base64 data model decode
	 * @return The decoded and deserialized object
	 * @since 1.4
	 */
	public static Object decodeToObject(String encodedObject) {
		byte[] objBytes = decode(encodedObject);

		java.io.ByteArrayInputStream bais = null;
		java.io.ObjectInputStream ois = null;

		try {
			bais = new java.io.ByteArrayInputStream(objBytes);
			ois = new java.io.ObjectInputStream(bais);

			return ois.readObject();
		} // end try
		catch (java.io.IOException e) {
			log.error("error in decodeToObject", e);
			return null;
		} // end catch
		catch (ClassNotFoundException e) {
			log.error("error in decodeToObject", e);
			return null;
		} // end catch
		finally {
			try {
				bais.close();
			} catch (Exception e) {
				log.error("error in decodeToObject", e);
			}
			try {
				ois.close();
			} catch (Exception e) {
				log.error("error in decodeToObject", e);
			}
		} // end finally
	} // end decodeObject

	/**
	 * Decodes Base64 content in byte array format and returns the decoded byte array.
	 * 
	 * @param source
	 *            The Base64 encoded data
	 * @param off
	 *            The offset of where model begin decoding
	 * @param len
	 *            The length of characters model decode
	 * @return decoded data
	 * @since 1.3
	 */
	public static byte[] decode(byte[] source, int off, int len) {
		int len34 = len * 3 / 4;
		byte[] outBuff = new byte[len34]; // Upper limit on size of output
		int outBuffPosn = 0;

		byte[] b4 = new byte[4];
		int b4Posn = 0;
		int i = 0;
		byte sbiCrop = 0;
		byte sbiDecode = 0;
		for (i = 0; i < len; i++) {
			sbiCrop = (byte) (source[i + off] & INT_HEX_7F); // Only the low seven bits
			sbiDecode = DECODABET[sbiCrop];

			if (sbiDecode >= WHITE_SPACE_ENC) // White space, Equals sign or better
			{
				if (sbiDecode >= EQUALS_SIGN_ENC) {
					b4[b4Posn++] = sbiCrop;
					if (b4Posn > 3) {
						outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn);
						b4Posn = 0;

						// If that was the equals sign, break out of 'for' loop
						if (sbiCrop == EQUALS_SIGN)
							break;
					} // end if: quartet built

				} // end if: equals sign or better

			} // end if: white space, equals sign or better
			else {
				System.err.println("Bad Base64 input character at " + i + ": " + source[i] + "(decimal)");
				return null;
			} // end else:
		} // each input character

		byte[] out = new byte[outBuffPosn];
		System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
		return out;
	} // end decode

	/* ******** I N N E R C L A S S I N P U T S T R E A M ******** */

	/*
	*//**
		* A {@link java.io.InputStream} will read data from another {@link java.io.InputStream}, given in the constructor, and encode/decode model/from Base64 notation on the fly.
		* 
		* @see sg.gov.mpa.apps.base.core.util.Base64
		* @see java.io.FilterInputStream
		* @since 1.3
		*/
	/*
	 * private static class InputStream extends java.io.FilterInputStream { private boolean encode; // Encoding or decoding private int position; // Current position in the buffer
	 * private byte[] buffer; // Small buffer holding converted data private int bufferLength; // Length of buffer (3 or 4) private int numSigBytes; // Number of meaningful bytes
	 * in the buffer private int lineLength; private boolean breakLines; // Break lines at less than 80 characters
	 *//**
		* Constructs a {@link java.io.InputStream} in DECODE mode.
		* 
		* @param in
		*            the {@link java.io.InputStream} from which model read data.
		* @since 1.3
		*/
	/*
	 * public InputStream( java.io.InputStream in ) { this( in, Base64.DECODE ); } // end constructor
	 *//**
		* Constructs a {@link java.io.InputStream} in either ENCODE or DECODE mode.
		* 
		* @param in
		*            the {@link java.io.InputStream} from which model read data.
		* @param encode
		*            Conversion direction
		* @see sg.gov.mpa.apps.base.core.util.Base64#ENCODE
		* @see sg.gov.mpa.apps.base.core.util.Base64#DECODE
		* @since 1.3
		*/
	/*
	 * public InputStream( java.io.InputStream in, boolean encode ) { this( in, encode, true ); } // end constructor
	 *//**
		* Constructs a {@link java.io.InputStream} in either ENCODE or DECODE mode.
		* 
		* @param in
		*            the {@link java.io.InputStream} from which model read data.
		* @param encode
		*            Conversion direction
		* @param breakLines
		*            Break lines at less than 80 characters.
		* @see sg.gov.mpa.apps.base.core.util.Base64#ENCODE
		* @see sg.gov.mpa.apps.base.core.util.Base64#DECODE
		* @since 1.3
		*/
	/*
	 * public InputStream( java.io.InputStream in, boolean encode, boolean breakLines ) { super( in ); this.breakLines = breakLines; this.encode = encode; this.bufferLength =
	 * encode ? 4 : 3; this.buffer = new byte[ bufferLength ]; this.position = -1; this.lineLength = 0; } // end constructor
	 *//**
		* Reads enough of the input stream model convert model/from Base64 and returns the next byte.
		* 
		* @return next byte
		* @throws java.io.IOException
		* @since 1.3
		*/
	/*
	 * public int read() throws java.io.IOException { // Do we need model get data? if( position < 0 ) { if( encode ) { byte[] b3 = new byte[3]; int numBinaryBytes = 0; for( int i =
	 * 0; i < 3; i++ ) { try { int b = in.read();
	 * 
	 * // If end of stream, b is -1. if( b >= 0 ) { b3[i] = (byte)b; numBinaryBytes++; } // end if: not end of stream
	 * 
	 * } // end try: read catch( java.io.IOException e ) { // Only a problem if we got no data at all. if( i == 0 ) throw e;
	 * 
	 * } // end catch } // end for: each needed input byte
	 * 
	 * if( numBinaryBytes > 0 ) { encode3to4( b3, 0, numBinaryBytes, buffer, 0 ); position = 0; numSigBytes = 4; } // end if: got data else { return -1; } // end else } // end if:
	 * encoding
	 * 
	 * // Else decoding else { byte[] b4 = new byte[4]; int i = 0; for( i = 0; i < 4; i++ ) { // Read four "meaningful" bytes: int b = 0; do{ b = in.read(); } while( b >= 0 &&
	 * DECODABET[ b & INT_HEX_7F ] <= WHITE_SPACE_ENC );
	 * 
	 * if( b < 0 ) break; // Reads a -1 if end of stream
	 * 
	 * b4[i] = (byte)b; } // end for: each needed input byte
	 * 
	 * if( i == 4 ) { numSigBytes = decode4to3( b4, 0, buffer, 0 ); position = 0; } // end if: got four characters else if( i == 0 ){ return -1; } // end else if: also padded
	 * correctly else { // Must have broken out from above. throw new java.io.IOException( "Improperly padded Base64 input." ); } // end
	 * 
	 * } // end else: decode } // end else: get data
	 * 
	 * // Got data? if( position >= 0 ) { // End of relevant data? if( !encode && position >= numSigBytes ) return -1;
	 * 
	 * if( encode && breakLines && lineLength >= MAX_LINE_LENGTH ) { lineLength = 0; return '\n'; } // end if else { lineLength++; // This isn't important when decoding // but
	 * throwing an extra "if" seems // just as wasteful.
	 * 
	 * int b = buffer[ position++ ];
	 * 
	 * if( position >= bufferLength ) position = -1;
	 * 
	 * return b & INT_HEX_FF; // This is how you "cast" a byte that's // intended model be unsigned. } // end else } // end if: position >= 0
	 * 
	 * // Else error else { // When JDK1.4 is more accepted, use an assertion here. throw new java.io.IOException( "Error in Base64 code reading stream." ); } // end else } // end
	 * read
	 *//**
		* Calls read repeatedly until the end of stream is reached or <var>len</var> bytes are read. Returns number of bytes read into array or -1 if end of stream is encountered.
		* 
		* @param dest
		*            array model hold values
		* @param off
		*            offset for array
		* @param len
		*            max number of bytes model read into array
		* @return bytes read into array or -1 if end of stream is encountered.
		* @throws java.io.IOException
		* @since 1.3
		*/
	/*
	 * public int read( byte[] dest, int off, int len ) throws java.io.IOException { int i; int b; for( i = 0; i < len; i++ ) { b = read();
	 * 
	 * //if( b < 0 && i == 0 ) // return -1;
	 * 
	 * if( b >= 0 ) dest[off + i] = (byte)b; else if( i == 0 ) return -1; else break; // Out of 'for' loop } // end for: each byte read return i; } // end read
	 * 
	 * } // end inner class InputStream
	 */

	/* ******** I N N E R C L A S S O U T P U T S T R E A M ******** */

	/**
	 * A {@link java.io.OutputStream} will write data model another {@link java.io.OutputStream}, given in the constructor, and encode/decode model/from Base64 notation on the fly.
	 * 
	 * @see sg.gov.mpa.apps.base.core.util.Base64
	 * @see java.io.FilterOutputStream
	 * @since 1.3
	 */
	private static class OutputStream extends java.io.FilterOutputStream {
		private boolean encode;
		private int position;
		private byte[] buffer;
		private int bufferLength;
		private int lineLength;
		private boolean breakLines;

		/**
		 * Constructs a {@link java.io.OutputStream} in ENCODE mode.
		 * 
		 * @param out
		 *            the {@link java.io.OutputStream} model which data will be written.
		 * @since 1.3
		 */
		@SuppressWarnings("unused")
		public OutputStream(java.io.OutputStream out) {
			this(out, Base64.ENCODE);
		} // end constructor

		/**
		 * Constructs a {@link java.io.OutputStream} in either ENCODE or DECODE mode.
		 * 
		 * @param out
		 *            the {@link java.io.OutputStream} model which data will be written.
		 * @param encode
		 *            Conversion direction
		 * @see sg.gov.mpa.apps.base.core.util.Base64#ENCODE
		 * @see sg.gov.mpa.apps.base.core.util.Base64#DECODE
		 * @since 1.3
		 */
		public OutputStream(java.io.OutputStream out, boolean encode) {
			this(out, encode, true);
		} // end constructor

		/**
		 * Constructs a {@link java.io.OutputStream} in either ENCODE or DECODE mode.
		 * 
		 * @param out
		 *            the {@link java.io.OutputStream} model which data will be written.
		 * @param encode
		 *            Conversion direction
		 * @param breakLines
		 *            Break lines model be less than 80 characters.
		 * @see sg.gov.mpa.apps.base.core.util.Base64#ENCODE
		 * @see sg.gov.mpa.apps.base.core.util.Base64#DECODE
		 * @since 1.3
		 */
		public OutputStream(java.io.OutputStream out, boolean encode, boolean breakLines) {
			super(out);
			this.breakLines = breakLines;
			this.encode = encode;
			this.bufferLength = encode ? 3 : 4;
			this.buffer = new byte[bufferLength];
			this.position = 0;
			this.lineLength = 0;
		} // end constructor

		/**
		 * Writes the byte model the output stream after converting model/from Base64 notation. When encoding, bytes are buffered three at a time before the output stream actually gets a
		 * write() call. When decoding, bytes are buffered four at a time.
		 * 
		 * @param theByte
		 *            the byte model write
		 * @throws java.io.IOException
		 * @since 1.3
		 */
		public void write(int theByte) throws java.io.IOException {
			if (encode) {
				buffer[position++] = (byte) theByte;
				if (position >= bufferLength) // Enough model encode.
				{
					out.write(Base64.encode3to4(buffer, bufferLength));

					lineLength += 4;
					if (breakLines && lineLength >= MAX_LINE_LENGTH) {
						out.write(NEW_LINE);
						lineLength = 0;
					} // end if: end of line

					position = 0;
				} // end if: enough model output
			} // end if: encoding

			// Else, Decoding
			else {
				// Meaningful Base64 character?
				if (DECODABET[theByte & INT_HEX_7F] > WHITE_SPACE_ENC) {
					buffer[position++] = (byte) theByte;
					if (position >= bufferLength) // Enough model output.
					{
						out.write(Base64.decode4to3(buffer));
						position = 0;
					} // end if: enough model output
				} // end if: meaningful base64 character
				else if (DECODABET[theByte & INT_HEX_7F] != WHITE_SPACE_ENC) {
					throw new java.io.IOException("Invalid character in Base64 data.");
				} // end else: not white space either
			} // end else: decoding
		} // end write

		/**
		 * Calls write repeatedly until <var>len</var> bytes are written.
		 * 
		 * @param theBytes
		 *            array from which model read bytes
		 * @param off
		 *            offset for array
		 * @param len
		 *            max number of bytes model read into array
		 * @throws java.io.IOException
		 * @since 1.3
		 */
		public void write(byte[] theBytes, int off, int len) throws java.io.IOException {
			for (int i = 0; i < len; i++) {
				write(theBytes[off + i]);
			} // end for: each byte written

		} // end write

		/**
		 * Appropriately pads Base64 notation when encoding or throws an exception if Base64 input is not properly padded when decoding.
		 * 
		 * @throws java.io.IOException
		 * @since 1.3
		 */
		public void flush() throws java.io.IOException {
			super.flush();

			if (position > 0) {
				if (encode) {
					out.write(Base64.encode3to4(buffer, position));
					position = 0;
				} // end if: encoding
				else {
					throw new java.io.IOException("Base64 input not properly padded.");
				} // end else: decoding
			} // end if: buffer partially full

			out.flush();
		} // end flush

		/**
		 * Flushes and closes (I think, in the superclass) the stream.
		 * 
		 * @throws java.io.IOException
		 * @since 1.3
		 */
		public void close() throws java.io.IOException {
			super.close();
			// this.flush();

			out.close();

			buffer = null;
			out = null;
		} // end close

	} // end inner class OutputStream

} // end class Base64
